The purpose of the NIH BRAIN Initiative Advanced Postdoctoral Career Transition Award to Promote Diversity (K99/R00) program is to enhance workforce diversity in the neuroscience workforce and maintain a strong cohort of new and talented, NIH-supported, independent investigators from diverse backgrounds in BRAIN Initiative research areas. This program is designed to facilitate a timely transition of outstanding postdoctoral researchers with a research and/or clinical doctorate degree from mentored, postdoctoral research positions to independent, tenure-track or equivalent faculty positions. The program will provide independent NIH research support during this transition in order to help awardees to launch competitive, independent research careers. This Funding Opportunity Announcement (FOA) is designed specifically for applicants proposing research that does not involve leading a clinical trial, a clinical trial feasibility study, or ancillary clinical trial. Applicants to this FOA are permitted to propose clinical trial research experience led by a mentor or co-mentor. Applicants proposing a clinical trial or an ancillary clinical trial to an ongoing clinical trial as lead investigator, should apply to the companion FOA.